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Biomedical subjects

T Ohshima

Publications and source records attributed to T Ohshima.

At least 109 records · Page 6Linked to original sources
PubMed2000

Improved synthesis of paroxetine hydrochloride propan-2-ol solvate through one of metabolites in humans, and characterization of the solvate crystals.

Paroxetine, a potent and selective inhibitor of 5-hydroxytryptamine (serotonin) uptake, was prepared through a piperidine derivative, which was reported to be one of the paroxetine metabolites in humans. Thus, the piperidine derivative was converted to its N-tert-butoxycarbonyl (N-Boc) derivative, which was then converted to N-Boc paroxetine. Paroxetine hydrochloride propan-2-ol (isopropyl alcohol (IPA)) solvate crystals were directly obtained from the N-Boc paroxetine by adding hydrogen chloride to the N-Boc paroxetine IPA solution. The amount of IPA content in the crystals was reduced by drying with a continuous change of powder X-ray diffraction patterns. Other characterizations of the solvate crystals were also conducted.

Crystallography, X-Ray↗
PubMed2000

CYP3A4 is a major isoform responsible for oxidation of 7-hydroxy-Delta(8)-tetrahydrocannabinol to 7-oxo-delta(8)-tetrahydrocannabinol in human liver microsomes.

The human liver enzyme microsomal alcohol oxygenase was able to oxidize both 7alpha- and 7beta-hydroxy-Delta(8)-tetrahydrocannabinol (7alpha- and 7beta-hydroxy-Delta(8)-THC) to 7-oxo-Delta(8)-THC. The oxidative activity was determined by using a panel of 12 individual cDNA-expressed human cytochrome P450s (CYPs) (1A1, 1A2, 2A6, 2B6, 2C8, 2C9-Arg, 2C9-Cys, 2C19, 2D6-Met, 2D6-Val, 2E1 and 3A4). Among the CYP isoforms examined, CYP3A4 showed the highest activity for both of substrates. The metabolism of 7alpha- and 7beta-hydroxy-Delta(8)-THC to 7-oxo-Delta(8)-THC was also detected for CYPs 1A1 (4.8% of CYP3A4), 1A2 (4.7%), 2A6 (2.3%), 2C8 (16.6%), and 2C9-Cys (5.4%), and CYPs 1A1 (0.4%), 2C8 (1.3%), 2C9-Arg (4.3%), and 2C9-Cys (0.9%), respectively. The 7alpha- and 7beta-hydroxy-Delta(8)-THC microsomal alcohol oxygenase activities in human liver were significantly inhibited by addition of 100 microM troleandomycin, 1 microM ketoconazole, and anti-CYP3A antibody, although these activities were not inhibited by 1 microM 7, 8-benzoflavone and 50 microM sulfaphenazole. When the substrates were incubated with the CYP3A4-expressed microsomes under oxygen-18 gas phase, atmospheric oxygen was incorporated into 35% of 7-oxo-Delta(8)-THC formed from 7alpha-OH-Delta(8)-THC, but only 12% of 7-oxo-Delta(8)-THC formed from 7beta-OH-Delta(8)-THC. These results indicate that CYP3A4 is a major isoform responsible for the oxidation of 7alpha- and 7beta-hydroxy-Delta(8)-THC to 7-oxo-Delta(8)-THC in liver microsomes of humans, although the oxidation mechanisms for 7alpha- and 7beta-hydroxy-Delta(8)-THC might be different.

Adolescent↗
PubMed2000

[The dynamics of cytokines and their related substances in skin wounds].

Molecular-pathological study on cytokines and their related substances in skin wound healing was performed from the view points of forensic pathology; 1. The dynamics of inflammatory cytokines such as interleukin (IL)-1 alpha, IL-1 beta, IL-6 and tumor necrosis factor-alpha (TNF alpha) during murine wound healing was examined at the levels of protein and mRNA. As for the results, the production of those inflammatory cytokines could be considered as one of the local vital reactions after wounding, and it was clarified that those inflammatory cytokines were one of the biological markers for forensic wound age determination. Practically, our immunohistochemical and morphometrical study with human skin wounds with different wound ages suggested that the ratios of IL-1 alpha-positive cells, considerably exceeding 30%, indicated a postinfliction interval of 1 day or less. 2. In mouse skin incision, a significant increase in IL-10 mRNA occurred between 30 and 180 min. The increased expression of IL-10 mRNA could be considered a vital reaction in skin wounds. Furthermore, it was clarified that IL-10 may have an important regulatory role in limiting the extent and duration of inflammatory response during skin wound healing. 3. Fas and Fas ligand (Fas L) were immunohistochemically detectable on macrophages and fibroblasts in skin wound healing process. Morphometrically, the number of cell expressing Fas and/or Fas L reached a peak at 6 days after wounding. Therefore, it is considered that apoptosis through Fas and Fas L may play an important role for reducing the cellularity during proliferative phase of wound healing in mice.

Animals↗
PubMed2000

[Detection of methamphetamine in a severely burned cadaver--a case report].

We report an autopsy case of a severely burned cadaver in which methamphetamine (MA) and amphetamine (A) were detected. A severely burned cadaver was found in a burned-out car on the seashore. At the autopsy, the drug screening test in the urine using Triage system gave positive result for MA and/or A. Qualitative analysis by gas chromatography/mass spectrometry (GC/MS) confirmed the presence of MA and A. The concentrations of MA and A (mumol/100 g) were 1.66 in the thermo-coagulated blood, 16.3 in the urine, 4.60 in the cerebrum, 4.11 in the lung, 7.84 in the liver, 0.94 in the skeletal muscle and 0.54 in the bone marrow. From these results, we concluded that the man had been under the moderate MA and A intoxication. The cause of death was diagnosed as the death of fire on the basis of autopsy findings, and the cadaver was identified as the owner of the car by the DNA typing. This case indicated the importance of drug screening tests in autopsy cases. Furthermore, the qualitative and quantitative analysis of MA and A should be successfully performed by GC/MS even in the case of severely burned cadaver.

Adult↗
PubMed1999

Hypernuclear acetylation in atherosclerotic lesions and activated vascular smooth muscle cells.

Recent studies have implicated acetylation of several nuclear proteins such as histones and p53 on their epsilon-portion of lysine residues in eukaryotic transcription. Here we raised a specific polyclonal antibody against epsilon-acetylated lysine. Using the antibody, we detected hypernuclear acetylation (HNA) in atherosclerotic vascular smooth muscle cells (VSMCs). Thrombin, a humoral factor known to cause activation and proliferation of VSMCs, strongly potentiated HNA in cultured VSMCs. MAP kinase pathway and a signal coactivator CREB binding protein (CBP) were involved in thrombin-induced HNA of VSMCs. Our results suggest that coactivators cooperating with signal-dependent transcription activators play an important role in atherosclerogenesis via HNA in VSMCs.

Acetylation↗
PubMed1999

CRM1 mediates nuclear export of nonstructural protein 2 from parvovirus minute virus of mice.

The nonstructural protein 2 (NS2) from parvovirus minute virus of mice (MVMp) is a 25-kDa polypeptide which localizes preferentially to the cytoplasm and associates with cellular proteins in cytoplasm. These lines of evidence suggest that NS2 is positively exported from the nucleus to cytoplasm and functions in cytoplasm. We report here that nuclear export of NS2 is inhibited by leptomycin B (LMB), a drug that specifically blocks nuclear export signal (NES)-chromosomal region maintenance 1 (CRM1) interactions. CRM1 binds specifically to the 81- to 106-amino-acid (aa) region of NS2, and the region of NS2 actually functions as a NES. Interestingly, this region appears to be distinct from a typical NES sequence, which consists of leucine-rich sequences. These results indicate that NS2 protein is continuously exported from the nucleus by a CRM1-dependent mechanism and suggest that CRM1 also exports to distinct type of NESs.

Amino Acid Sequence↗
PubMed1999

The NAD-dependent glutamate dehydrogenase from the hyperthermophilic archaeon Pyrobaculum islandicum: cloning, sequencing, and expression of the enzyme gene(1).

The NAD-dependent glutamate dehydrogenase (GluDH) gene from the hyperthermophilic archaeon Pyrobaculum islandicum was cloned and expressed in Escherichia coli. Analysis of the nucleotide sequence revealed an open reading frame of 1266 bp encoding a protein of 421 amino acids with a molecular weight of 46,905. In the alignment of the amino acid sequence with those of mesophilic Clostridium symbiosum NAD-dependent GluDH and hyperthermophilic NADP-dependent enzymes from Thermococcus profundus and Pyrococcus furiosus, substitutions in the residues involved in dinucleotide binding were observed. On the other hand, the residues involved in glutamate binding were well conserved. This is the first description of the primary structure of NAD-dependent GluDH in hyperthermophilic archaea.

Amino Acid Sequence↗
PubMed1999

Migration defects of cdk5(-/-) neurons in the developing cerebellum is cell autonomous.

Cyclin-dependent kinase 5 (Cdk5) is a member of the family of cell cycle-related kinases. Previous neuropathological analysis of cdk5(-/-) mice showed significant changes in CNS development in regions from cerebral cortex to brainstem. Among the defects in these animals, a disruption of the normal pattern of cell migrations in cerebellum was particularly apparent, including a pronounced abnormality in the location of cerebellar Purkinje cells. Complete analysis of this brain region is hampered in the mutant because most of cerebellar morphogenesis occurs after birth and the cdk5(-/-) mice die in the perinatal period. To overcome this disadvantage, we have generated chimeric mice by injection of cdk5(-/-) embryonic stem cells into host blastocysts. Analysis of the cerebellum from the resulting cdk5(-/-) left arrow over right arrow cdk5(+/+) chimeric mice shows that the abnormal location of the mutant Purkinje cells is a cell-autonomous defect. In addition, significant numbers of granule cells remain located in the molecular layer, suggesting a failure to complete migration from the external to the internal granule cell layer. In contrast to the Purkinje and granule cell populations, all three of the deep cerebellar nuclear cell groupings form correctly and are composed of cells of both mutant and wild-type genotypes. Despite similarities of the cdk5(-/-) phenotype to that reported in reeler and mdab-1(-/-) (scrambler/yotari) mutant brains, reelin and disabled-1 mRNA were found to be normal in cdk5(-/-) brain. Together, the data further support the hypothesis that Cdk5 activity is required for specific components of neuronal migration that are differentially required by different neuronal cell types and by even a single neuronal cell type at different developmental stages.

Aging↗
PubMed1999

Aging accentuates and bone marrow transplantation ameliorates metabolic defects in Fabry disease mice.

Fabry disease is an X-linked metabolic disorder caused by a deficiency of alpha-galactosidase A (alpha-Gal A). The enzyme defect leads to the systemic accumulation of glycosphingolipids with alpha-galactosyl moieties consisting predominantly of globotriaosylceramide (Gb3). In patients with this disorder, glycolipid deposition in endothelial cells leads to renal failure and cardiac and cerebrovascular disease. Recently, we generated alpha-Gal A gene knockout mouse lines and described the phenotype of 10-week-old mice. In the present study, we characterize the progression of the disease with aging and explore the effects of bone marrow transplantation (BMT) on the phenotype. Histopathological analysis of alpha-Gal A -/0 mice revealed subclinical lesions in the Kupffer cells in the liver and macrophages in the skin with no gross lesions in the endothelial cells. Gb3 accumulation and pathological lesions in the affected organs increased with age. Treatment with BMT from the wild-type mice resulted in the clearance of accumulated Gb3 in the liver, spleen, and heart with concomitant elevation of alpha-Gal A activity. These findings suggest that BMT may have a potential role in the management of patients with Fabry disease.

Aging↗
PubMed1999

Simultaneous determination of local anesthetics including ester-type anesthetics in human plasma and urine by gas chromatography-mass spectrometry with solid-phase extraction.

The present study describes the simultaneous determination of seven different kinds of local anesthetics and one metabolite by GC-MS with solid-state extraction: Mepivacaine, propitocaine, lidocaine, procaine (an ester-type local anesthetics), cocaine, tetracaine (an ester-type local anesthetics), dibucaine (Dib) and monoethylglycinexylidide (a metabolite of lidocaine) were clearly separated from each other and simultaneously determined by GC-MS using a DB-1 open tubular column. Their recoveries ranged from 73-95% at the target concentrations of 1.00, 10.0 and 100 microg/ml in plasma, urine and water. Coefficients of variation of the recoveries ranged from 2.3-13.1% at these concentrations. The quantitation limits of the method were approximately 100 ng/ml for monoethylglycinexylidide, propitocaine, procaine, cocaine, tetracaine and dibucaine, and 50 ng/ml for lidocaine and mepivacaine. This method was applied to specimens of patients who had been treated with drip infusion of lidocaine, and revealed that simultaneous determination of lidocaine and monoethylglycinexylidide in the blood and urine was possible.

Anesthetics, Local↗
PubMed1999

Morphological findings of 'cardiac concussion' due to experimental blunt impact to the precordial region.

The dog's precordial region at the sternum was impacted with a mechanical elastic-cord propelled impactor at the velocity of 8.0 m/s. The left and right intraventricular pressures and electrocardiogram (ECG) were monitored continuously for 60 min after the impact. The micro- and ultra-structure of myocardium were examined. Localization of myocardial myoglobin (Mb), creatine kinase BB (CK-BB) and creatine kinase MM (CK-MM) as well as plasma membrane permeability were studied by immunohistochemical and lanthanum probe techniques. Upon the impact, abrupt over-pressures within both ventricles were recorded with transient depression of the left ventricular systolic pressure. In all the dogs, some rhythm- and conduction-disorders were noted, which lasted transiently and resumed to normal sinus rhythm. At autopsy, no gross injuries of the heart were detected, and microscopic examination showed no visible myocardial lesions. However, immunohistochemically, focal patchy loss of myocardial Mb, CK-BB and CK-MM was identified with scattered deposition of these substances between myocardial fibers elsewhere. Such changes as relaxed myofibrils with widened I band, contracted myofibrils and broken cristae of the mitochondria were observed in myocardial ultrastructure. Lanthanum particles deposited inside the mitochondria. These results indicate that increase in cardiac cell membrane permeability and ultrastructural damage in myocardium may be involved even in cardiac concussion.

Animals↗
PubMed1999

Regulatory role of endogenous interleukin-10 in cutaneous inflammatory response of murine wound healing.

This study investigated the role of endogenous interleukin (IL)-10 in cutaneous wound healing. Both IL-10 mRNA and protein were detectable in murine incised wounds for 10 days after injury. The IL-10 protein level peaked 3 h after incision, returned to the normal level by 24 h, but increased again to another peak at 72 h. In situ hybridization studies and immunostaining revealed that epidermal cells and infiltrating mononuclear cells were the major source of IL-10. Neutralizing antibody studies demonstrated that IL-10 inhibited the infiltration of neutrophils and macrophages toward the site of injury. IL-10 also inhibited overexpression of C-C chemokines (monocyte chemoattractant protein-1, macrophage inflammatory protein-1alpha) and proinflammatory cytokines (IL-1beta, IL-6, tumor necrosis factor-alpha) in vivo. These results suggest that IL-10 may play an important regulatory role in the phase-specific infiltration of neutrophils and macrophages as well as the cytokine production in the inflammatory response of cutaneous wound healing.

Animals↗
PubMed1999

Anesthesia for insertion of a Dumon stent in a patient with a large tracheo-esophageal fistula.

PURPOSE: To present the anesthetic management for the insertion of a Dumon silicon stent to the trachea of a patient with a large tracheo-esophageal fistula. The aim of the stent insertion was to seal the fistula in order to prevent aspiration of esophageal content and subsequent pneumonitis. CLINICAL FEATURES: A 45-yr-old man with a large tracheo-esophageal fistula was scheduled for the insertion of the Dumon stent. Since placement of the stent necessitates the insertion of a rigid bronchoscope, under general anesthesia, with its tip just proximal to the fistula, controlled ventilation was expected to be difficult to achieve because of the diversion of oxygen through the large fistula to the esophagus. We successfully ventilated the lungs, after the fistula was sealed using a large balloon which was inserted in the esophagus, and the stent insertion was completed uneventfully. CONCLUSION: Anesthesia for procedures involving the central airway is challenging. This report describes a simple and practical method to facilitate ventilation by temporary seal of a tracheo-esophageal fistula using a modified esophageal balloon.

Anesthesia, General↗
PubMed1999

Immunohistochemical and morphometrical study on the temporal expression of interleukin-1alpha (IL-1alpha) in human skin wounds for forensic wound age determination.

An immunohistochemical and morphometrical study on the temporal expression of interleukin-1alpha (IL-1alpha) was performed on 40 human skin wounds with different wound ages. Immunohistochemically, polymorphonuclear neutrophils mainly showed positive reactions for IL-1alpha in wounds aged between 4 h and 1 day, but with increasing wound age, neutrophils were no longer present, and macrophages and fibroblasts were positively stained. Morphometrically, the ratio of the number of IL-1alpha-positive infiltrating cells to the total number of infiltrating cells was evaluated. A considerable increase in the IL-1alpha-positive cell ratio was observed in wound specimens aged 4 h to 1 day, and the maximum ratio was 46.5% in a 7 hold wound. The mean value of the IL-1alpha-positive ratio in 10 wound specimens with different wound ages between 4 h and 1 day was 32.8 +/- 9.7%. In most cases the ratio of IL-1alpha-positive cells gradually decreased in wounds aged between 1.5 and 21 days to less than 30%, and the mean value was 17.5 +/- 7.2% (n = 27). These results suggest that ratios of IL-1alpha-positive cells considerably exceeding 30%, indicate a postinfliction interval of 1 day or less.

Adolescent↗
PubMed1999

Proportion of geometrical hydroperoxide isomers generated by radical oxidation of methyl linoleate in homogeneous solution and in aqueous emulsion.

The proportion of geometrical hydroperoxide isomers generated by aerobic oxidation of methyl linoleate (18:2 Me) in either aqueous emulsion consisting of Tris-HCl buffer (pH 7.4) or in a homogeneous dichloromethane solution was determined to understand the mechanism of lipid oxidation in different reaction systems. Four geometrical isomers were generated after oxidation of 18:2 Me in dichloromethane: methyl 13-hydroperoxy-cis-9, trans-11-octadecadienoate, methyl 13-hydroperoxy-trans-9,trans-11-octadecadienoate, methyl 9-hydroperoxy-trans-10,cis-12-octadecadienoate, and methyl 9-hydroperoxy-trans-10, trans-12-octadecadienoate in the ratios of 1:4:1:4, respectively. The ratios between each isomer did not change until the peroxide value (PV) increased to 58 meq/kg. Oxidation of 18:2 Me in aqueous emulsion yielded the same geometrical isomers of hydroperoxide. However, the ratios were different: 3:2:3:2 until the PV increased to 110 meq/kg. Predominant (60%) formation of trans,trans hydroperoxide isomers was obtained in the oxidation of a mixture of 18:2 Me and methyl laurate (12:0 Me). These results are interpreted to reflect the importance of the concentration of hydrogen atom-donating equivalents to the kinetic preference for different products. The high effective concentration of hydrogen donors in the oxidation of 18:2 Me in emulsions favored the formation of the less stable cis,trans isomers. The lower concentration of hydrogen donor in the dichloromethane solution effectively slowed hydrogen donation and led to the strong preference for the more stable trans,trans isomers. This interpretation was further tested by preparing emulsions of 18:2 Me and 12:0 Me to dilute concentration of hydrogen-donating species using the nonhydrogen-donating 12:0 Me. Consistent with the proposed hypothesis, the proportion of trans,trans isomers increased as a result of 12:0 Me addition.

Chromatography, High Pressure Liquid↗